# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def diameterOfBinaryTree(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        self.ans = 0
        self.traverse(root)
        return self.ans

    def traverse(self, root):
        if not root: return 0
        left = self.traverse(root.left)
        right = self.traverse(root.right)
        self.ans = max(self.ans, left + right)
        print('left', left)
        print('right', right)
        print('self.ans', self.ans)
        return max(left, right) + 1







    """
        Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a
        binary tree is the length of the longest path between any two nodes in a tree. This path may or may
        not pass through the root.

        Example:
        Given a binary tree
                  1
                 / \
                2   3
               / \
              4   5
        Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].

        Note: The length of path between two nodes is represented by the number of edges between them.
    """
